amcewen
commented
7 years ago Removing the ground connection on the audio connection, to avoid ground loops made little difference. Ferrite beads on the audio lines similarly didn't help much.
So, ideally having an i2s DAC and amp (like the Pi Zero box) but with a rotary volume control is what we're after. And more powerful than our current set up.
Some options (not verified that they'll all work with a Pi)...
DACs:
- https://www.aliexpress.com/item/UDA1380-Board-UDA-1380-Module-Stereo-Audio-Codecs-Decoder-Based-on-I2S-Interface/548266169.html $9.99, has input as well as output
- http://store.digilentinc.com/pmod-i2s-stereo-audio-output/ $13.99
Amps:
- https://www.aliexpress.com/item/1PCS-YDA138-DC5-8V-Mono-12W-Amplifier-Board-Class-D-replace-PAM8403/32762847981.html $5.80 mono
- https://www.aliexpress.com/item/LM386-Super-mini-amplifier-board-low-power-consumption-3-12V-Cost-performance-is-better-than-that/32664972721.html $2.19 through-hole, need to assemble ourselves
- https://www.aliexpress.com/item/DIY-suite-DC-2-12V-TDA2822-Double-audio-power-amplifier-board-suite-DIY-TDA2822-Dual-channel/32662250547.html $8.78 through-hole, need to assemble ourselves
- http://www.ebay.co.uk/itm/-/151862056655?var=451055165479 (our current amp module)
There's also the Voice HAT that came in the Google AIY kit, but it's not clear if that will be on sale separately at all
The Brains with analogue audio often have some noise on the audio output, particularly when the Pi is active (it seems to synchronize with the disk activity LED on the Pi, for example).